The tens digit of a two-digit number is two more than its unit digit. The two-digit number is 7 times the sum of the digits. Find the units digits?
A. 1
B. 2
C. 3
D. 4
E. None of these
Explanation:
Let the two-digit number be 10a + b
a = b + 2 — (1)
10a + b = 7(a + b) => a = 2b
Substituting a = 2b in equation (1), we get
2b = b + 2 => b = 2
Hence the units digit is: 2.